After soaking up almost relentless pressure in a goalless first half, the Reds came flying out of the blocks after the restart with left-back Reece Devine racing forward and French teenager Hannibal Mejbril converting the resulting pull-back.
England Under-18 defender Teden Mengi doubled our lead in the 65th minute, by firing home like a striker after being played into City's box by Mark Helm.
Liam Delap pulled one back for the Blues in the 75th minute after dispossessing Will Fish and bursting through to lob our goalkeeper Ondrej Mastny. But more resolute defending, and a fine save by Mastny to deny City's top scorer Cole Palmer in the 90th minute, secured the win for Neil Ryan's young Reds.